What sdk is producing the errors: MapQuest.js or the MapQuest Leaflet plugin v2?
What is the error?
If it's a http vs https error, make sure the protocol for the download matches the protocol for the requesting page.

While the SDK has been updated since this issue was noticed, the backing transaction counter has not. I believe the issue is that the response to the transaction request is blank and FireFox throws an error on the blank response. The request wasn't intended to have a functional response since all credential and configuration requests happen on the map instantiation. I'm forwarding this on to the team who is currently working on implementing a new SDK we hope to release later this year or early next year.

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